We can use the powershell cmdlet Set-DistributionGroup to configure delivery restriction with the parameter -AcceptMessagesOnlyFrom. It’s easy to create a powershell command to add multiple office 365 users to the -AcceptMessagesOnlyFrom attribute on the DL object but when doing this you’ll find that only the last one in the list has been added. This is because the attribute is an array. You can view this using the following command.